Fix Synology Moments WAN Backup Issues

Problems with Synology Moments Photo Backup over WAN and mobile networks

The goal of Synology Moments was to make backing up private photos easy. You can upload photos from your phone, connect to your NAS, and they will sync automatically. That’s the plan, at least.

In reality, a lot of people have trouble backing up their photos when they try to do it over WAN or mobile networks. Backups stop, connections fail, uploads stop halfway through, or the app won’t sync when you’re not on the same network.

Moments itself almost never causes these problems. Most of the time, they have to do with how the network is set up, NAT, firewall rules, or how mobile networks work. To fix them for good, you need to know what caused them in the first place.

Why WAN and mobile backups are not the same as local sync

Backups are easy when your phone and NAS are both on the same Wi-Fi network. The device talks to the NAS IP address directly.

Traffic must still go through: over WAN or mobile networks

• Your router
• Translation of NAT
• Rules for the firewall
• Limitations set by ISPs
• Filtering by mobile carrier

This makes things more complicated. Backups don’t work if any part of the path is set up wrong.

Reasons Why Moments WAN Backup Fails Often

1. Port forwarding that isn’t correct

Moments needs outside access to DSM services. Mobile devices can’t connect to the NAS if your router doesn’t forward ports correctly.

A lot of people try to forward default DSM ports without making sure they are safe. Some people don’t even remember to forward HTTPS traffic.

Moments can’t connect if the external port is blocked.

2. Double NAT or ISP Limits

Some ISPs put their customers behind Carrier-Grade NAT. In this case, your router does not have a real public IP address. Port forwarding won’t work because the ISP is in charge of the external gateway.

Signs include:

• Connection works in the area
• Fails on the outside
• Port forwarding looks right, but you still can’t get to it

You might need to ask your ISP for a public IP address or use a VPN-based connection instead of being directly exposed to the problem.

3. Restrictions or throttling on mobile networks

Sometimes, mobile carriers limit background data activity or connections that stay open. When the app isn’t open, big photo uploads might stop.

Background app restrictions can also get in the way on iOS and Android. Settings for optimizing the battery may pause Moments while they are uploading.

Allowing background data for the app and turning off strict battery restrictions usually fixes problems that happen from time to time.

4. Problems with SSL Certificates

Mobile devices may not connect if DSM uses a self-signed certificate. This can make uploads fail without anyone noticing.

Using a trusted certificate like Let’s Encrypt makes encrypted communication more reliable and stops handshake errors.

5. QuickConnect’s Limits

QuickConnect makes it easier to access things from a distance, but it might not work well for uploading large files over mobile networks. It can add latency and throughput limits, though, compared to direct VPN or properly set up reverse proxy setups.

A VPN connection usually works better for large photo libraries.

Performance Problems on the NAS Side

Even when networking is set up correctly, performance can still be bad if:

The NAS CPU is too busy indexing, the storage is almost full, snapshots are running while the upload is happening, and the RAM is not enough.

Moments uses AI to index and process metadata. Uploading thousands of photos at once can use up all the resources on lower-end NAS models.

When you upload files, checking DSM Resource Monitor can help you find bottlenecks.

Best Ways to Make WAN Backups Stable

For a reliable backup of photos on your phone or computer:

1. Use HTTPS and make sure your SSL certificate is valid.
2. Don’t let the internet see DSM directly.
3. Use a VPN to safely connect from afar.
4. Set up the right rules for your firewall.
5. Turn off aggressive battery optimization on your phone.
6. Set up indexing for times when the system isn’t being used much.
7. Make sure there is enough free space to store things.

These changes make things safer and work better.

Moving to Synology Photos for More Stability

If you still use Synology Moments on DSM 6, moving to DSM 7 and Synology Photos can make things run faster and make indexing more stable. Synology Photos takes Moments’ AI features and makes them work better with the system and use resources more efficiently.

After migration, WAN backup reliability often gets better.

About Epis Technology

Epis Technology helps businesses set up safe ways for people to access Synology servers from outside the office. The team doesn’t just use basic port forwarding; they also use structured VPN configurations, reverse proxy solutions, and secure firewall segmentation to make sure WAN communication stays stable. Epis Technology makes sure that photo backups work well on mobile networks while keeping strong security controls by optimizing NAS performance, SSL configuration, and snapshot scheduling.